Equity and Distributions (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			6 Months Ended					12 Months Ended		6 Months Ended			1 Months Ended		6 Months Ended	5 Months Ended	3 Months Ended
	Jun. 30, 2011		Jun. 30, 2010	Jun. 30, 2011		Jun. 30, 2010	Dec. 31, 2010		Dec. 31, 2010 Common units [Member] Holdings Merger [Member]	Dec. 31, 2009 Class B units [Member] TEPPCO Merger [Member]	Jun. 30, 2011 Common units [Member]	Jun. 30, 2011 Class B units [Member]	Jun. 30, 2011 Treasury Units [Member]	May 31, 2011 Distribution Reinvestment Plan [Member]	Feb. 28, 2011 Distribution Reinvestment Plan [Member]	Jun. 30, 2011 Distribution Reinvestment Plan [Member]	May 31, 2011 Employee Unit Purchase Plan [Member]	Jun. 30, 2011 Enterprise [Member] Cash Distribution [Member]	Mar. 31, 2011 Enterprise [Member] Cash Distribution [Member]
Mergers [Line Items]
Common unit exchange ratio in connection with merger									1.5
Common units issued in connection with merger (in units)									208,813,454
Number of quarters Class B units are not entitled to regular quarterly cash distributions										16
Number of Designated Units (in units)									30,610,000
Summary of changes in outstanding units [Roll Forward]
Balance, December 31, 2010 (in units)											843,681,572	4,520,431	0
Common units issued in connection with DRIP and EUPP (in units)											1,111,905	0	0	551,058	474,706	1,025,764	86,141
Restricted common units issued (in units)											1,359,230	0	0
Forfeiture of restricted common units (in units)											(75,857)	0	0
Acquisition of treasury units (in units)											(226,601)	0	226,601
Cancellation of treasury units (in units)											0	0	(226,601)
Other (in units)											(14,301)	0	0
Balance, June 30, 2011 (in units)											845,835,948	4,520,431	0
Conversion of restricted units to common units (in units)											828,545
Registration Statements and Equity Offerings [Line Items]
Remaining units available for issuance (in units)																27,389,108
Net Cash Proceeds from Sale of Common Units [Abstract]
Number of Common Units Issued (in units)											1,111,905	0	0	551,058	474,706	1,025,764	86,141
Net Cash Proceeds				$ 45.1		$ 0								$ 21.9	$ 19.6	$ 41.5	$ 3.6
Maximum common units permitted under the plan (in units)																	1,200,000
Accumulated Other Comprehensive Income (Loss) [Abstract]
Commodity derivative instruments	(61.2)	[1]		(61.2)	[1]		(31.8)	[1]
Interest rate derivative instruments	(45.1)	[1]		(45.1)	[1]		(2.1)	[1]
Foreign currency translation adjustment	1.7	[2]		1.7	[2]		1.7	[2]
Pension and postretirement benefit plans	(1.0)			(1.0)			(0.4)
Proportionate share of other comprehensive loss of Energy Transfer Equity	(1.7)			(1.7)			(1.0)
Subtotal	(107.3)			(107.3)			(33.6)
Amounts attributable to noncontrolling interest	1.1			1.1			1.1
Total accumulated other comprehensive loss in partners' equity	(106.2)			(106.2)			(32.5)
Limited partners of Duncan Energy Partners:
Third-party owners of Duncan Energy Partners	407.3	[3]		407.3	[3]		410.4	[3]
Related party owners of Duncan Energy Partners	1.7	[4]		1.7	[4]		1.7	[4]
Joint venture partners	113.2	[5]		113.2	[5]		115.6	[5]
Accumulated other comprehensive loss attributable to noncontrolling interest	(1.1)			(1.1)			(1.1)
Total noncontrolling interest	521.1			521.1			526.6
Components of net income attributable to noncontrolling interest [Abstract]
Limited partners of Enterprise	0		284.2	0		590.7
Limited partners of Duncan Energy Partners	9.4		9.6	17.3		18.3
Joint venture partners	5.4		6.5	11.3		13.8
Total	14.8		300.3	28.6		622.8
Cash distributions paid to noncontrolling interest:
Limited partners of Enterprise				0		683.9
Limited partners of Duncan Energy Partners				21.9		21.3
Joint venture partners				12.9		15.3
Total cash distributions paid to noncontrolling interest				34.8		720.5
Cash contributions from noncontrolling interest:
Limited partners of Enterprise				0		960.0
Limited partners of Duncan Energy Partners				1.5		0.8
Joint venture partners				1.1		1.1
Total cash contributions from noncontrolling interest				$ 2.6		$ 961.9
Distributions to Partners [Abstract]
Distribution Per Common Unit (in dollars per unit)																		$ 0.6050	$ 0.5975
Record Date																		2011-07-29	2011-04-29
Payment Date																		2011-08-10	2011-05-06

[1] See Note 4 for additional information regarding these components of accumulated other comprehensive income (loss).

[2] Relates to transactions of our Canadian NGL marketing subsidiary.

[3] Consists of non-affiliate public unitholders of Duncan Energy Partners.

[4] Consists of unitholders of Duncan Energy Partners that are related party affiliates.

[5] Represents third-party ownership interests in joint ventures that we consolidate, including Seminole Pipeline Company, Tri-States NGL Pipeline L.L.C., Independence Hub LLC, Rio Grande Pipeline Company, and Wilprise Pipeline Company LLC.